Electric furnace



April 19, 1932. A, HANSQN 1,854,374

ELECTRIQ FURNACE Filed April l1, 1930 2 Sheets-Sheet l APl'il19, 1932- A, J. HANsoN 1,854,374

ELECTRI C FURNACE Filed April 11. 1930 2 Ysheets-sheet 2 Patented Apr.'19, 1932 UNITED STATES PATENT OFFICE ALBRT J'. HANSON, OF ARLINGTON, MASSACHUSETTS, ASSIGN OR T0 AMERICAN ELEC- TRIC FURNACE COMPANY, OF SOUTH BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS ELECTRIC FUBNACE Application led April 11,

This invention relates to a furnace and particularly to a type of electric furnace that may be employed for the purpose of hardening and tempering, or otherwise heat-treating metals or articles of manufacture constructed of metal.

The object of the invention is to provide a furnace of. the character mentioned in which large quantities of relatively small metallic articles may be easily handled and quickly and effectively heat treated, said articles while being treated being located in a mass in a perforated container and the latter being rotated continuously in the same direction in the path of a-current of heated air which is caused to be recirculated through the container and mass of articles therein in such a manner that all of the articles will be subjected to heat of a uniform temperature.

The invention consists in an electric furnace as set forth in the following specification and particularly as pointed out in the claims thereof.

Referring to the drawings:

Fig. 1 represents a sectional elevation of an electric furnace embodying my invention.

Fig. 2 is a horizontalV sectional view through the furnace.

Fig. 3 is a detail view of a portion of the driving mechanism for the rotatable work supporting member and fan.

Like numerals refer to like parts throughout the several views of the drawings.

In the drawings, 5 represents a casing embodying` therein an outer wall 6 and an iuner wall 7, between which is a suitable heatinsulating material 8. .The casing` 5 rests upon a base 9 which in turn is supported upon a plurality of legs 10. Located within the casing 5 is a cylindrical partition 11 which divides the interior of the casing into an outer heat-generating compartment 12 and an inner heat-treating compartment 13. The partition 11 is concentrically positioned with respect to the inner wall 7 of the casing.

The heat-treating compartment 13 is closed at the top by a, cover plate 14' which has annular flangesv l5 and 16 extending therearound and projecting upwardly from the top surface thereof, thereby forming an an- 1930. Serial No. 443,387.

nular groove 17 which is filled with sand 18, or other suitable material, to form a seal for a cover 19 when the latter is located in its closed position. An opening 2O extends through the cover plate 14 in order that access may be had to the interior of the heat-treating compartment 13.

The top o the casing 5, or that portion of said casing t iat is located between the outer and inner walls 6 and 7 respectively and which contains the heat-insulating material 8, is closed by a cover plate 21 the underside of which rests upon the top edge of the iange 16 of the cover plate 14 and the top edge of the outer wall 6.` An opening 22 extends through the cover plate 21 in oi'der that the cover 19may be inserted therethrough and ilnlay rest upon the ange of the cover plate The partition 11 has a series of openings 23 provided therein atone side thereof and another series of openings 24 in the side thereof opposite the openings 23, and the openings 24 communicate with a passageway 25 which in turn communicates with the outer heat-generatlng compartment 12. Located within the compartment 12 are a plurality of electric heating elements 26 of any suitable type and well known in the art, said elements being mounted upon insulators 2T which are in turn mounted in any suitable manner upon the inner Wall 7 of the casing 5. The electric heating elements are concentrically positioned relatively-to the .vertical median line of the casing 5 within the heat-generating(- compartment 12 and are spaced apart at regular intervals therearound, being electrically connected together in a well-known manner.

Mounted in the casing 5 upon the vertical median line thereof is a bearing 28 in which a vertical shaft 29 is rotatably mounted. A work supporting member 30 in the form of a table is located within the heat-treating compartment 13 and is rigidly fastened to the upper end portion of the 4shaft 29. A basket 31 constructed of heavy open mesh wire and constituting a work holding container is supported upon the table 30.

The shaft 29 projects downwardly through the casing 5 and base 9, and rigidly secured at its lower end is a worm gear 32 which is enclosed within a casing 33 fastened to the underside of the base-9. The worm gear 32 is driven by a worm -34 fast to a countershaft 35, one end of which is mounted in bearings 36 provided therefor in the casing 33. Thel is-rotatably mounted in a 'bearing 45 fastened to tll'casing 5 at a point midway betweenl the top and bottom thereof. A sprocket 46 is fast to the shaft 44 on theV outer end portion thereof anda fan 47 is rigidly secured to a ortion of the shaft 44 which projects into the heatenerating compartment 12. The fan 47 is ocated directly in front of an opening 48 at the outer end of the passage 25 and the blades of the fan are so positioned that when the fan is rotated a suction will be created within the passageway 25, thereby creating a current of heated air through the heattreating compartment 13 and container 31 in a direction transversely of the axis of the rotatable table 30.

The cover 19, that is provided for closing the opening 20 into the heat-treating compartment 13, is raised and lowered and swung laterally of the casing 5 by a mechanism as follows z-The cover 19 is suspended by means of a link 49 from the extremity of a lever 50 which is pivoted at 51 to a bracket 52 which is rotatably mounted upon a bearing member 53 in turn supported upon the cover plate 21. A spring 54 is secured to the brack- 'et 52 and lever 50 in a manner to form a counter-balance for the cover 19. An actuating member 55 is pivoted at 56 to the bracket V52 and is provided with a handle 57. The member 55 is slotted at 58 in order that the lever 50 may project therethrough and the lower end portion 59 ofthe slot 58 is adapted to engage the lower edge of the lever 50. To lift the cover 19 the outer end portion of the handle 57 is grasped and pulled downwardly therebyv imparting a rocking movement to the actuating member 55 and causing the portion 59 of said member to engage the lower edge of the lever 50 thereby lifting the end portion of the latter from which the cover 19 is suspended. After the cover has been lifted above the top portion of the cover plate 21, the handle 57 is swung sidewise causing the bracket 52 to be rotated upon the bearing member 53 and swinging the cover 19 froml above the opening 20.

'lhe temperature of the heating area within the casing 5 is regulated automatically by mechanism as follows z-Extending through the casing 5 from the outer wall 6 to the inner wall 7 at any suitable location therein, but preferably at a point adjacent to where the heated air passes from the outer compartment 12 to the inner compartment 13, is a tube 69 in which a thermo-couple instrument 6l is mounted. rlhe instrument 61 is of a type well known in' the art and a sensitive extremity thereof projects into the outer compartment 12 adjacent to the point where the heated air passes into the inner compartment through the openings 23. The instrument 61.

is connected by wires 62 and 63 with an automatic control device 64 also well known in the art, said device being set to open and close in a well-known manner the electric circuit of which the electric heating elements 26 form a part.

The general operation of the device hereinbefore specifically described is a follows Assuming that the work which is to be heat treated is located within the container 31 and the latter has been placed upon the rotatable table 30, the heat-treating compartment 13 is closed by means of the cover 19. The electric motor 40 is then started, causing the chain 39 to be driven in a manner to rotate the countershaft 35, thereby driving the worm 34 and the worm gear 32, rotating the shaft 29 and 'table 3() which is fastened thereto. At the same time the chain 39 causes the shaft 44 to be rotated to operate the fan 47 and the latter is driven in such a manner that a suction will be created within the passageway 25 and a current of heated air will be caused to be circulated through the heat-treating compartment 13 and through the container 31, in which the work is located, in a direction transversely of the axis of the table 30. After passing through the heat-treating compartment, the air is blown by the fan 47 in opposite directions around the heat-generating compartment 12 where it is reheated by passing under the influences of the various heating elements. The heated air then passes from the compartment 12 to the compartment 13, being blown through the openings 23 provided in the partition 11 and is again circulated through the compartment 13. v

During the operation of the device the automatic heat-regulating means is set to maintain the temperature of the heating area at a predetermined degree of heat, said mechanism functioning in a well-known manner to open or close the electric circuit to the heating elements. In this manner all of the work which is located within the container 31 is subjected to heat of a uniform temperature.

After the material has been suliciently heat through the opening 22, after which a sidewise motion of the handlel will cause the cover to be swunglaterally from above said opening.

I claim:

l. An electric furnace having, in combination, a casing, a partition within said casing dividing the interior thereof into inner and outer heating compartments, a work-supporting member within the inner compartment, means to impart a rotary motion to said work-supporting member, elect-ric heating means within the outer compartment, and

means positioned above the work supporting member to recirculate heated air in a general horizontal direction through both of said compartments.

2. An electric furnace having, in combination, a casing, a partition Within said casing dividing the interior thereof into inner and outer heating compartments,a work-supporting member within the inner compartment, means to impart a rotary motion to said work-supporting member, electric heating means within the outer compartment positioned concentric to the axis of the worksupporting member, and means to recirculate heated air horizontally in opposite directions through the outer compartment and across the inner compartment in a direction transversely of the axis of the container.

3. An electric furnace having, in combination, a casing,a partition within said casing dividing the interior thereof into inner and outer heat-ing compartments, said partltion being provided with openings therein, a table at the bottom of the inner compartment, a perforated work-holding container lupon said table, means to impart a rotary. motion .to the table, a plurality of electric heating elements within the outer compartment, and means positioned midway the height of the container to create a current of heated air within the inner compartment Y and through the container and openings in the partition in a direction transversely of the axis of the table.

4. An electric furnace having, in combination, a casing, a partition within said casing dividing the interior thereof into inner and outer heatinv compartments, a work-supporting member Within the inner compartment, means to impart arotary motion to said work-supporting member, electric heatin means within the outer compartment, and means to recirculate heated air in a general horizontal direction past the heating means and'through said' compartments, said air passing through the outer compartment in opposite direct-ions and through the inner compartment in a direction transversely of l the axis of the work-supporting member.

outer heating compartments, a cover for the inner compartment, a work-supporting member within the inner compartment, means to impart a rotary motion to said work-supporting member, electric heating means within the outer compartment, means to recirculate heated airhorizontally in opposite directions through the outer compartment and across the inner compartment in a direction transversely of the -axis of the container, and means to .raise and lower said cover and also move the same laterally of the casing when in a raised position.

6. An electric furnace having, in combination, a casing, a partition within said casing dividing the interior thereof into inner and outer heating compartments, a cover for the inner compartment, means to counterbalance said cover, means to seal the cover when the latter is closed, a work-supporting table at the bottom of the inner compartment, means located beneath the furnace to impart a 'rotary motion to said work-supporting table, electric heating means within the outer compartment, means to recirculate heated air in a general horizontal direction around the heating means and through said compartments, and means to raise and lower the casing when in a raised position.

7. An electric furnace having, in combination, a casing, a partition within said casing dividing the interior thereof into inner and outer heating compartments, said partition being provided with openings therein, a table within the inner compartment, a perforated work-holding container vupon said table, 4 means to impart a rotary motion to the table, a plurality of electric heating elements within the outer compartment, means to force heated air in opposite directions through the outer compartment and through the inner compartment and through the container and openings in the partition in a direction transversely of the axis of the table, and automatic means for regulating the temperature within the heating compartments, said means embodying therein a sensitive instrument ex-` posed to the heat of the outer compartment adjacent to the point where the heated air passes therefrom into the inner compartment.

In testimony whereof I have hereunto set 

